Q:
Boroughs? Census Areas?  What are they?  What happened to 'county'?

A:

Alaska is not divided into counties but rather into organized and the so-called unorganized borough. Organized boroughs are similar to counties, however, and each of the such units are supervised by a small assembly. The unorganized borough includes more than 80% of the state's area but less than 20% of its population. It is administered by the state government; for statistical purposes it is divided into census areas (divisions).

Use of the term "borough" was a controversial part of Alaska's Constitutional plan and debated at length by the delegates. It was adopted largely to avoid legal and political connotations of the traditional county. Alaska’s boroughs were intended to be more versatile and powerful than counties. The failure of some local economies to generate enough revenue to support separate counties was an important issue.  The desire to use a model that would reflect the unique character of Alaska was another.

For the most part, organized boroughs were formed in those areas where economies were better developed. The large portion of the state that has not incorporated as an organized borough is designated the unorganized borough.

The primary difference between boroughs and census areas is that boroughs have an organized area-wide government, while census areas do not. The entire area of the state outside of organized boroughs is treated as one large unorganized borough.  In addition, census areas are not defined by the State, but rather by the United States Census Bureau.